As shown in FIG. 11, a conventional double brake structure for a caster wheel 2 contains a pressing member 23 pressed downwardly so as to stop two rollers, wherein when the pressing member 23 is pressed, an end portion 231 of the pressing member 23 rotates along a tangent angle 241 of a sliding holder 24, and the end portion 231 pushes the sliding block 24 to press a resilient element 27 by using a long peripheral fringe 232, a fixing pin 25 moves to abut against a recess 211 of a body 21 along an elongated hole 201 of a seat 20, thus stopping the body 21 movement. In addition, a locking block 26 is pushed by an elastic member 28 to move with the sliding block 24, such that the locking block 26 retains in a notch 222 of a projection 221 of a rotary shaft 22, hence the seat 20 is fixed so that the caster wheel 2 cannot roll and rotate.
Referring further to FIG. 12, another conventional caster wheel with double braking functions contains a pressing member 30, when the pressing member 30 is pressed, an pushing end 301 of the pressing member 30 is biased against a pushing block 31, and then the pushing block 31 moves downwardly along a groove 32, in the meantime, an abutting face 311 of the pushing block 31 pushes a tilted contacting face 331 of a sliding seat 33 so that the sliding seat 33 presses a first spring 34 horizontally, such that a fixing pin 332 of the sliding seat 33 retains in one of two recesses 41 of two rollers 4, and the two rollers 4 cannot rotate, thereafter a ball 36 in an orifice 35 is forced by a shoulder 333 of the sliding seat 33 so as to move upwardly to press a second spring 37 in the orifice 35, hence an extension 381 of a stopping post 38 engages with one of positioning holes 392 of a fix member 391 of a rotary column 39, thus stopping the rotary column 39 rotation.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.